A GLIMPSE THROUGH TIME The Washington Street Viaduct (now the Courtland Street Bridge) is seen here from the top of the Capitol Building shortly after the bridge opened in 1907. Flanking the viaduct on either side is the two-block long Louisville and Nashville (L&N) Railroad Freight Depot. The roof of the Georgia Railroad Freight Depot can be spotted behind the building on the left. Today the L&N lines are owned and operated by CSX Transportation. Clickhereto see what this looks like now.
Transportation improvements are sometimes wrought with road blocks – even in 1906. The Washington Street Viaduct was no exception. Two weeks after the bid opening, property owners along the project limits threatened to sue for damages if the viaduct was constructed. Businesses along the north end of the project included a boarding house, two restaurants, a barbershop, a farrier, and the Pearl Laundry Marking Company. The complaint was that these businesses would incur severe damages because their establishments would no longer be at street level.
To make matters worse, competitive bidders on the project played out their rivalries in the editorial pages of the Atlanta Constitution.
Foundation work continues through the month of March under Collins Street at Georgia State University
Bridge columns and caps will be poured under the the south end of the Bridge near the Georgia Railroad Freight Depot
There will be limited access to GSU parking decks from south Collins Street
By the end of March, ALL access to Collins Street will be closed
February's frigid temps and icy precipitation did not "freeze" progress on the Courtland Street Bridge Replacement. Weather delays are limited so the project stays on schedule to minimize construction impacts.
The use of micropiles on the Courtland Street Bridge Project is one of the Accelerated Bridge Construction methods that will allow total construction of the bridge - from the ground up - to be completed in nine months instead of two years. The road closure and detours that cause traffic and socio-economic impacts will be kept to six months. Here's why...
While traffic is still flowing on top of the old bridge,...
the foundations for the new bridge are being built underneath.
Dr. Fernado Lizzi, an Italian civil engineer, is credited with developing micropile technology for the restoration of buildings and monuments damaged during World War II. Their use spread worldwide. Micropiles have been used in US structural engineering since the late 1980's. As the cornerstone of the new Courtland Street Bridge's foundation structure, micropiles are a deep foundation element. They are constructed using high-strength, small-diameter steel casings and threaded steel bars. The technology is well suited for this project because of the restricted access and low headroom conditions that exist.
Workers first excavate for the pile cap. The location for each micropile is identified and marked. Because of the low headroom existing under the bridge, workers use a compact drill rig to insert the casings. Depending on the subsurface conditions, the piles could be drilled to a depth of 80 feet or more into solid bedrock.
Once the inner drill string is removed, an all-threaded reinforced steel bar is inserted into the casing. Grout is then pumped into the drill hole and casing to complete the micropile and bond it to the bedrock. Each micropile is designed to carry a 550,000 pound load.
Reinforcing steel (rebar) bars are installed before the pile cap is poured - encasing them in concrete along with the micropiles. This, in essence, distributes the load between the columns and the piles. Next, forms are erected and the columns are poured. The final product, comprised of micropiles, footings, column(s) and cap is known collectively as the bridge "bent." The new Courtland Street Bridge will have 13 bents, two of which will be single columns. That's essentially one new bent for every three existing bents. The new bridge is designed to support greater loads, so the bents will be placed further apart and the beams that will eventually go on top of the caps will be longer.
Our mailing address is:
Georgia Department of Transportation
Communications, Suite 1800
One Georgia Center
600 West Peachtree Street, N.W.
Atlanta, GA 30308
